1. Field of the Invention
The present invention relates to an image display apparatus in which a laser light source apparatus using a semiconductor laser is incorporated.
2. Description of Related Art
In recent years, laser light has drawn attention as a light source of an image display apparatus which can perform large-screen display, and technology development of a semiconductor laser has been facilitated to form this laser light. Compared with an ultra-high pressure mercury lamp (UHP lamp) conventionally used as a light source of an image display apparatus or a light-emitting diode (LED) recently used in a small-sized image display apparatus, a light source using a semiconductor laser light source has advantages including good color reproducibility, instant light up, long life, and high efficiency in electrical/optical conversion.
Hereinafter, a conventional laser light source apparatus is explained. As described in Japanese Patent Laid-open Publication No. 2010-32796, for example, the conventional light source apparatus has a red color laser light source, a blue color laser light source, and a green color laser light source as short-wavelength laser light sources which consecutively emit red color (R) laser light, blue color (B) laser light, and green color (G) laser light, respectively. The red color laser light source and the blue color laser light source are semiconductor lasers that emit red color laser light and blue color laser light, respectively. The green color laser light source has a configuration in which wavelength conversion is performed on laser light of the semiconductor laser so as to emit green color laser light.
The above-described conventional image display apparatus uses three colors of laser light as light sources, and projects images having good color reproducibility. In the conventional image display apparatus, however, quality of projected images deteriorates due to an increase in temperature of the laser light sources when the conventional image display apparatus is operated for a long period of time.
The three laser light sources each have different temperature characteristics. Basically, an increase in temperature of a laser light source causes a decrease in its light output. Light output of a red color laser light source apparatus particularly decreases in association with a temperature increase. Thus, the light output of the red color laser light source apparatus is likely to become weak as the temperature increases when the conventional image display apparatus is operated for a long period of time. As one color, for example, of three color laser light becomes weak in this way, the conventional image display apparatus cannot output images of high quality due to an imbalance in color.